Instance volume limits - Amazon Elastic Compute Cloud

Instance volume limits

The maximum number of volumes that your instance can have depends on the operating system and instance type. When considering how many volumes to add to your instance, you should consider whether you need increased I/O bandwidth or increased storage capacity.

Nitro System volume limits

Instances built on the Nitro System support a maximum number of attachments, which are shared between network interfaces, EBS volumes, and NVMe instance store volumes. Every instance has at least one network interface attachment. NVMe instance store volumes are automatically attached. For more information, see Elastic network interfaces and Instance store volumes.

Most of these instances support a maximum of 28 attachments. For example, if you have no additional network interface attachments on an EBS-only instance, you can attach up to 27 EBS volumes to it. If you have one additional network interface on an instance with 2 NVMe instance store volumes, you can attach 24 EBS volumes to it.

For other instances, the following limits apply:

  • Most bare metal instances support a maximum of 31 EBS volumes.

  • u-6tb1.metal, u-9tb1.metal, and u-12tb1.metal instances support a maximum of 19 EBS volumes if launched after March 12, 2020 and a maximum of 14 EBS volumes otherwise. To attach more than 14 EBS volumes to an instance launched before March 12, 2020, contact your account team to upgrade the instance at no additional cost.

  • u-18tb1.metal and u-24tb1.metal instances support a maximum of 19 EBS volumes.

Windows-specific volume limits

The following table shows the volume limits for Windows instances based on the driver used. Note that these numbers include the root volume, plus any attached instance store volumes and EBS volumes.

Important

Attaching more than the following volumes to a Windows instance is supported on a best effort basis only and is not guaranteed.

Driver Volume Limit

AWS PV

26

Citrix PV

26

Red Hat PV

17

We do not recommend that you give a Windows instance more than 26 volumes with AWS PV or Citrix PV drivers, as it is likely to cause performance issues.

To determine which PV drivers your instance is using, or to upgrade your Windows instance from Red Hat to Citrix PV drivers, see Upgrading PV drivers on Windows instances.

For more information about how device names related to volumes, see Mapping disks to volumes on your Windows instance.

Bandwidth versus capacity

For consistent and predictable bandwidth use cases, use EBS-optimized or 10 Gigabit network connectivity instances and General Purpose SSD or Provisioned IOPS SSD volumes. Follow the guidance in Amazon EBS–optimized instances to match the IOPS you have provisioned for your volumes to the bandwidth available from your instances for maximum performance. For RAID configurations, many administrators find that arrays larger than 8 volumes have diminished performance returns due to increased I/O overhead. Test your individual application performance and tune it as required.